IT Services blog

PDF: what is it good for?

PDF (Portable Document Format) is one of the few file formats familiar to most computer users, technical and non-technical alike. This is a testament to how widespread it has become since its conception nearly twenty years ago in California.

During the 1990s, developers at Adobe Systems in San Jose identified a need within their company to be able to electronically distribute documents totally independent of platform or software availability, whilst maintaining the layout. Conceptually this meant effectively “printing” a page (which could contain both images and text) to electronic paper which could then be sent via email or other electronic means without affecting the content.

After a couple of years of development Acrobat, a tool for reading and creating PDFs, was launched in the Summer of 1993. At first the software for both reading and creating PDFs had to be paid for but a year later, upon the release of version 2.0 of the software, the reader was made available free and the format really took off.

Regular enhancements were made over the next few years, including functional hyperlinks within PDFs, the embedding of meta-information (allowing PDFs to be meaningfully indexed by search engines) and the inclusion of editable form fields to allow people to complete applications and other forms onscreen.

Eventually PDF was released as an Open Standard which meant that other software manufacturers were free to write PDF authoring and reading functionality into their applications. Currently PDFs can be directly created from all Apple Mac software and from Office 2007 for Windows PCs. There are also a number of free PDF creation utilities available for Windows PCs and the online service Google Docs allows documents to be saved as PDFs.

A PDF is…

In its simplest form a PDF can be thought of as “a picture of a document”. Its electronic form is analogous to the electronic version of a faxed document when in transit. PDF is intended for the distribution of documents in their final edition when no further editing is intended or required. In many areas the PDF has replaced printed documentation as the definitive version of manuals, instructions and forms.

Sussex Postgraduates now have to submit one PDF copy of their thesis, along with the bound copies; there are ITS FAQs concerning this:

A PDF is not…

…something that can be edited
Wanting to edit a PDF makes as much sense as wanting to edit your morning paper. If you need to edit a PDF that someone has sent you then you should question as to whether PDF was the correct form to use in the first place. Often another file format such as Word (.doc or .docx) or Rich Text Format (.rtf) would be more appropriate for distribution of the content in these instances.

However it is usually possible to extract text from a PDF using cut and paste unless restrictions have specifically been put in place by the PDF’s author to prevent this.

…a replacement for HTML web pages
The fact that PDFs are easily created and can be distributed via the web means that it can be tempting simply to upload a PDF instead of writing a web page. However, if the document being uploaded is intended solely for reading onscreen within the context of a web site it should be in HTML format. Quite apart from the fact that print documents are written differently from screen documents due to a different paradigm, PDFs also present a number of accessibility problems when used online.

There is of course nothing wrong with making PDFs available online for download and printing (for example hardware and software manuals) but be wary of using them as the sole source of information on any topic.

But I really need to…
However, if you do have a pressing need to edit a PDF but don’t have access to the original file, help is at hand.

The software package PDF Converter Pro is available free to students and staff at Sussex and is a powerful tool for creating and manipulating PDF files. Whilst it doesn’t allow you to edit a PDF in the same way you would a Word document, it does allow a certain amount of minor editing such as changing individual words or inserting blocks of text.